Relativistic Effects on Electron Transport in Magnetic Alloys

Abstract

We study the relativistic effects on electron transport in spin-polarized metals and random alloys on ab initio level using the fully relativistic tight-binding linear muffin-tin-orbital (TB-LMTO) method. We employ a Kubo linear-response approach adapted to disordered multisublattice systems in which the chemical disorder is described in terms of the coherent potential approximation (CPA). The CPA vertex corrections are included. We calculate both the Fermi surface and Fermi sea terms of the full conductivity tensor. We find that in cubic ferromagnetic 3d transition metals (Fe, Co, Ni) and their random binary alloys (Ni-Fe, Fe-Si) the Fermi sea term in the anomalous Hall conductivity is small in comparison with the Fermi surface term, however, in more complicated structures, such as hexagonal Co and selected Co-based Heusler alloys, it becomes important. We find an overall good agreement between the theory and experimental data.